my 89 maxima runs too cold. Now that it is colder her in western Washington it takes forever to warm up. I can drive about 15 miles before the temp gauge gets near normal. The outside temp. is only about 40.

Any ideas for me to check?

Thanks

Larry

 

Check your engine thermostat.

A good diagnostic test for a bad thermostat is as follows: The engine will warm up when using a lot of fuel as in going up a long hill, but the temperature guage will move cooler when using little fuel as in going down a long hill. Usually, the temperature guage should never change position after the engine warms up.

A properly operating thermostat will throttle down the supply of cool water, sourced from the botton of the radiator, from entering the engine when the engine is not producing much heat.

 

I would be inclined to just go ahead and change the thermostat (assuming the car drives okay other than this problem). The thermostat has a wax pellet inside it that's designed to melt at a certain temperature and open the thermostat so that coolant can stop just recirculating around the water jackets around the engine (when it's warming up) and instead go through the radiator to cool it. When thermostats fail, they're designed to fail "open" so that while cold drivability sucks, the car won't overheat and will be normal once it's warmed up.

 

I just replaced the thermostat and it's no better. I tested the old thermostat and it opened at 180. The new one I put in was 170.

Now what?

thanks

larry

 

Hmm, I took a quick look through my FSM and there's nothing about the car warming up too slowly. How does the car drive? Is the warm up problem creating drivability problems or is it just that you're not getting any heat until 15 minutes go by?

Also, are you sure the old or new thermostat is installed in the right direction? I haven't seen the one for our cars, but I vaguely recall some kind of problem if you install the thermostat upside down (can't remember what it does though).

If the car drives okay and the thermostat is okay, then I'm stumped

Anyone else?